ocp: Fixes for OCP 2.5 Telemetry DA1 FIFO Event Parsing

[jeff-lien-wdc]

This commit fixes several issues related to parsing the Telemetry DA 1 and 2 Event FIFO's.

Fixes parsing of VU Event Data. Added checking for VU data. Removed the vu_event_identifier field from the debug event class structs since it's not guaranteed to be there. Added nvme_ocp_common_dbg_evt_class_vu_data to be used to access the VU data.

Added checking for NULL pointers

Added a check for the end of the Event FIFO entries that will
break from the while loop when detected.

[igaw]

Could you squash the commits together when this change is ready to be merged? Thanks.

[jeff-lien-wdc]

Could you squash the commits together when this change is ready to be merged? Thanks.

@igaw Yes, I will do that. Just wrapping up some fixes and changes from Brandon's review comments. Those should be done today.

[igaw]

I forgot to add @arthurshau for a review.

[arthurshau]

LGTM

[igaw]

Thanks!